Studies of the relative importance of iron and aluminium in the sorption of phosphate by some Australian soils

Soil Research ◽  
1965 ◽  
Vol 3 (1) ◽  
pp. 31 ◽  
Author(s):  
SM Bromfield
Keyword(s):  
Ammonium Oxalate ◽  
Correlation Coefficients ◽  
Sodium Dithionite ◽  
Relative Importance ◽  
Dilute Acid ◽  
Phosphate Sorption ◽  
Acid Washing ◽  
Incomplete Removal ◽  
Acid Acid ◽  
A Minor

Phosphate sorption by 47 acid surface soils was correlated with the amounts of iron and aluminium extracted from them by ammonium oxalate at pH 3.2. The correlation coefficients, when all soils were considered, were highest for sorption and aluminium. For certain groups of soils, iron or iron plus aluminium gave higher coefficients than did aluminium. The relative contributions of iron and aluminium to phosphate sorption could not be accurately assessed from these correlation coefficients because iron and aluminium themselves were positively correlated. Eleven of the forty-seven soils were chosen for determinations of the effect of selective removal of iron and aluminium on their ability to sorb phosphate. Soils usually sorbed less phosphate after various amounts of their iron and aluminium had been extracted chemically. Many of them, however, still sorbed large amounts of phosphate in spite of the removal of reducible iron and acid-soluble aluminium. Soils and haematite extracted with sodium dithionite in acetate at pH 5.0 usually sorbed more phosphate than untreated samples. This was due largely to the incomplete removal of reduced iron and could be prevented by washing with dilute acid. Acid washing after dithionite treatment caused sorption by the soils to fall below the values for the untreated samples and virtually destroyed that of the oxide. It also removed much aluminium from the soils. The amount by which sorption fell below that of the untreated samples could be accounted for largely by this aluminium. It was concluded tentatively that, for most of the soils, phosphate sorption was due to acid-soluble aluminium and to sorption sites which were non-reducible and insoluble in dilute acid. The contribution of reducible iron in the original soils remains in doubt, but it could be a minor one.

scholarly journals Dependence of the phosphate sorption capacity on the aluminium and iron in Finnish soils

1963 ◽  
Vol 35 (4) ◽  
pp. 165-177
Author(s):  
Armi Kaila
Keyword(s):  
Organic Carbon ◽  
Sorption Capacity ◽  
Soil Ph ◽  
Ammonium Oxalate ◽  
Correlation Coefficients ◽  
Fine Sand ◽  
Clay Soils ◽  
Phosphate Sorption ◽  
Soluble Iron ◽  
Soil Groups

An attempt was made to study to what extent the capacity of the more or less acid soils in Finland to sorb phosphate may be explained on the basis of their content of aluminium and iron. The indicator of the phosphate sorption capacity was calculated on the basis of the Freundlich adsorption isotherm according to the procedure proposed by TERÄSVUORI (8). The material consisted of 390 samples from cultivated and virgin soils representing both topsoils and subsoils. The indicator of the phosphate sorption capacity, the coefficient k, varied in the present material from 40 to 1510. The mean values (with the confidence limits at the 95 per cent level) were for the 109 samples of sand and fine sand soils 290 ± 17, for the 103 samples of loam and silt soils 201 ± 24, for the 151 clay soils 308 ± 20, and for the 27 humus soils 236 ± 41. The total linear correlation coefficients between k and the soil pH, and its contents of organic carbon or clay were low or negligible in most of the soil groups. The correlation of k with the content of aluminium extracted by Tamm’s acid ammonium oxalate was fairly close in the clay soils (r = 0.84***), lower in the sand and fine sand soils (r = 0.77***), and in the loam and silt soils, and in the humus soils it was rather poor (r = 0.65*** and 0.63*** resp.). The elimination of the effect of the ammonium oxalate soluble iron decreased the correlation in the two latter groups quite markedly (to 0.32** and 0.37 resp.), while the corresponding decrease in the coefficients for the former groups was less significant (to 0.64*** and 0.75*** resp.). The elimination of the effect of the ammonium oxalate soluble aluminium, on the other hand, decreased the correlation coefficients between k and the ammonium oxalate soluble iron in the sand and fine sand soils from 0.59*** to 0.26**, in the loam and silt soils from 0.73*** to 0.54***, in the clay soils from 0.70*** to 0.51***, and in the humus soils from 0.68*** to 0.49*. The part of variation in k which could be explained on the basis of the variation in the contents of aluminium and iron was different in the different kind of soils. According to the coefficients of determination and the coefficients of multiple determination, the variance in the aluminium content determined 59 per cent of the variance in k in the sand and fine sand soils and 70 per cent in the clay soils; considering also the content of iron increased this part to 61 per cent and 78 per cent, resp. In the loam and silt soils the variation in the iron content explained 53 per cent of the variation in k, in the humus soils this percentage was 47. Considering both aluminium and iron, the proportion of the variance in k which could be explained in these two groups was increased to 60 per cent and 54 per cent, resp. Thus, in addition to the contents of ammonium oxalate soluble iron and aluminium, other factors must be found to explain the variation in the phosphate sorption capacity, particularly in other soil groups than in the clay soils. The soil pH and its content of organic carbon obviously play only a minor role among these ctors.

scholarly journals Weathering features of a remineralizer in soil under different land uses

2021 ◽  
Vol 56 ◽  
Author(s):  
Rafael Cipriano da Silva ◽  
Edilene Pereira Ferreira ◽  
Antonio Carlos de Azevedo
Keyword(s):  
Amorphous Phase ◽  
Ammonium Oxalate ◽  
Total Content ◽  
Sodium Dithionite ◽  
Land Uses ◽  
Elephant Grass ◽  
X Ray ◽  
Time Periods ◽  
Gains And Losses

Abstract The objective of this work was to analyze the mineralogical, morphological, and compositional modifications resulting from the weathering of diabase grains buried into soil under different land uses for up to 378 days. Samples of comminuted diabase were put into polyester bags and buried into soil under corn crop, elephant grass, and woods, being unburied and evaluated after four time periods. The samples of the remineralizer (RM) were analyzed by X-ray diffractometry, total chemical analysis, scanning electron microscopy, and Al (Ald and Alo) and Fe (Fed and Feo) contents extracted by sodium dithionite-citrate-bicarbonate (DCB) and ammonium oxalate (AAO) solutions. Plagioclases and pyroxenes were the most weathered minerals in all three land uses and showed the same pattern of elemental gains and losses. The characterization of Fe and Al solubility in DCB and AAO showed that the greatest change in these elements was from the lithogenic and crystalline to the pedogenic and amorphous phase, when compared with their total content. Plagioclases and pyroxenes were the most weathered minerals, and Fe and Al show a great transfer from the crystalline to the amorphous phase, with values up to 26 and 175, respectively, for the ratios between bags with RM/Feo and RM-control and bags with RM/Alo and RM-control.

scholarly journals Physical, chemical and mineralogical attributes of a representative group of soils from the Eastern Amazon, Brazil

2018 ◽  
Author(s):  
Edna Santos de Souza ◽  
Antonio Rodrigues Fernandes ◽  
Anderson Martins de Souza Braz ◽  
Fábio Júnior de Oliveira ◽  
Luís Reynaldo Ferracciú Alleoni ◽  
...  
Keyword(s):  
Descriptive Analysis ◽  
Sustainable Use ◽  
Ammonium Oxalate ◽  
Principal Component ◽  
Sodium Dithionite ◽  
Physical Chemical ◽  
Low Concentrations ◽  
High Concentrations ◽  
And Cluster Analysis ◽  
Al Oxide

Abstract. Amazonian soils are heterogeneous. However, few studies have been carried out in the Amazon, mainly because of its considerable size, which complicates the collection of data and the ability to plan for the sustainable use of natural resources. In this study, the physical, chemical and mineralogical attributes of soils in the state of Pará, Brazil, were characterized by examining particle size, fertility, silicon (Si) extracted by sodium hydroxide (NaOH), and iron (Fe), aluminum (Al), and manganese (Mn) extracted by sulfuric acid (H2SO4), sodium dithionite-citrate-bicarbonate and ammonium oxalate + oxalic acid. Descriptive analysis, multivariate principal component analysis and cluster analysis were carried out. The soils had low concentrations of bioavailable P, Ca2+, Mg2+ and K+ and high concentrations of Al3+ and Si and Al oxide contents were higher in Cambisols. Contents of Fe and Mn oxides were higher in both Cambisols and Nitosols, which are rich in oxidic minerals. Multivariate analysis indicated an association between the content of organic carbon and the pH, P, Ca, Mg and K contents. An additional association was observed between clay, potential acidity and the Fe and Al oxide contents.

Comparisons of structural iron reduction in smectites by bacteria and dithionite: II. A variable-temperature Mössbauer spectroscopic study of Garfield nontronite

2009 ◽  
Vol 81 (8) ◽  
pp. 1499-1509 ◽  
Author(s):  
Fabiana R. Ribeiro ◽  
José D. Fabris ◽  
Joel E. Kostka ◽  
Peter Komadel ◽  
Joseph W. Stucki
Keyword(s):  
Iron Reduction ◽  
Magnetic Order ◽  
Variable Temperature ◽  
Bacterial Species ◽  
Shewanella Oneidensis ◽  
Sodium Dithionite ◽  
Abiotic Reduction ◽  
A Minor ◽  
Structural Iron ◽  
Mössbauer Analysis

The reduction of structural Fe in smectite may be mediated either abiotically by reaction with chemical reducing agents or biotically by reaction with various bacterial species. The effects of abiotic reduction on clay surface chemistry are much better known than the effects of biotic reduction, and differences between them are still in need of investigation. The purpose of the present study was to compare the effects of dithionite (abiotic) and bacteria (biotic) reduction of structural Fe in nontronite on the clay structure as observed by variable-temperature Mössbauer spectroscopy. Biotic reduction was accomplished by incubating Na-saturated Garfield nontronite (sample API 33a) with Shewanella oneidensis strain MR-1 (FeII/total Fe achieved was ~17 %). Partial abiotic reduction (FeII/total Fe ~23 %) was achieved using pH-buffered sodium dithionite. The nontronite was also reduced abiotically to FeII/total Fe ~96 %. Parallel samples were reoxidized by bubbling O2 gas through the reduced suspensions at room temperature prior to Mössbauer analysis at 77 and 4 K. At 77 K, the reduction treatments all gave spectra composed of doublets for structural FeII and FeIII in the nontronite. The spectra for reoxidized samples were largely restored to that of the unaltered sample, except for the sample reduced to 96 %. At 4 K, the spectrum for the 96 % reduced sample was highly complex and clearly reflected magnetic order in the sample. When partially reduced, the spectrum also exhibited magnetic order, but the features were completely different depending on whether reduced biotically or abiotically. The biotically reduced sample appeared to contain distinctly separate domains of FeII and FeIII within the structure, whereas partial abiotic reduction produced a spectrum representative of FeII–FeIII pairs as the dominant domain type. The 4 K spectra of the partially reduced, fully reoxidized samples were virtually the same as at 77 K, whereas reoxidation of the 96 % reduced sample produced a spectrum consisting of a magnetically ordered sextet with a minor contribution from a FeII doublet, indicating significant structural alterations compared to the unaltered sample.

The Formation of the ‘Crusade Idea’

1970 ◽  
Vol 21 (1) ◽  
pp. 11-31 ◽  
Author(s):  
E. O. Blake
Keyword(s):  
The Other ◽  
Christian Tradition ◽  
Relative Importance ◽  
First Crusade ◽  
Holy Places ◽  
Unique Experience ◽  
The Subject ◽  
Set Up ◽  
The One ◽  
A Minor

In order to understand the crusading movement it has always been necessary to define what was understood by the ‘crusade’ as a religious exercise within the Christian tradition. This attempt to identify the ‘crusade idea’ goes back to the earliest commentators on the First Crusade, but has gained increasing vitality during the last thirty years. It is not a matter of weighing the relative importance of, on the one hand, the religious and, on the other, the secular or political motives, but of describing the content of the nova religio as such. In this sense Erdmann, who first set up the subject as capable of disciplined study, traced the antecedents in socio-religious forms of behaviour without which the Kreuzzugsidee could not have been conceived, regarding it as in its essentials formulated at the launching of the First Crusade, with Jerusalem as only a minor and ancillary target. Alphandéry, to single out another notable contributor to this type of study, diagnosed the dramatic emergence of a distinctive idée de croisade during the very course of the First Crusade, concentrated on the deliverance of the Holy Places, a unique experience never to be wholly repeated. Another notion of the ‘crusade’ was developed by Rousset—an institution de salut with its characteristic ideology, entertained generally during the first half of the twelfth century.5 There are studies also of the ideas associated with crusading in the crusade appeals, preaching, justification and criticism of the twelfth and thirteenth centuries, in the forms of procedure, and in Latin and vernacular poetry.

scholarly journals Using woody genera for phytogeographic regionalization at a medium scale: a case study of Italy

Botany ◽  
2016 ◽  
Vol 94 (7) ◽  
pp. 533-542 ◽  
Author(s):  
Giovanna Abbate ◽  
Elisabetta Scassellati ◽  
Sandro Bonacquisti ◽  
Mauro Iberite ◽  
Marta Latini ◽  
...  
Keyword(s):  
Correlation Coefficients ◽  
Strongly Correlated ◽  
Floristic Diversity ◽  
Sampling Strategies ◽  
Coarse Scale ◽  
Taxonomic Level ◽  
A Minor ◽  
Endemic Flora ◽  
East West

We present a phytogeographic regionalization based on native woody flora, identifying the most useful taxonomic level, geographic variables, and orographic pattern, selecting Italy as a case study. We generated seven distance matrices among the 20 administrative regions, and using Pearson’s correlation coefficients and PCA, we verified whether distances between regions were invariant across the different sampling strategies. Once this invariance was established, we focused on genera representation. We defined two orographic indices and performed Kruskal–Wish multidimensional scaling and K-means clustering to assess Italy’s phytogeographic regionalization. A major north–south and a minor east–west gradient described the relationships between regions. Floristic diversity was strongly correlated with the region’s orography, with hills being the most important orographic feature that increased plant diversity; the effect of the orographic patterns was independent from the geographic clines observed. Despite the coarse scale, our phytogeographic regionalization comprising six clusters (variables = 133 woody genera) was consistent with previous ones based on the endemic flora (variables = 1371 units) or on bioclimatic approaches. In particular, the phytogeographic uniqueness of Northern and peninsular Italy, and of Sardinia Island, was confirmed. The next step will be to test our method at a finer scale.

scholarly journals The Adoption of Tubewell Technology in Pakistan

1990 ◽  
Vol 29 (3-4) ◽  
pp. 291-303 ◽  
Author(s):  
M. Jamil Chaudhry
Keyword(s):  
Rural Areas ◽  
Farm Households ◽  
Class Structure ◽  
Small Farmers ◽  
Relative Importance ◽  
Farm Sector ◽  
Vital Importance ◽  
Rural Income ◽  
Tube Well ◽  
A Minor

The use and adoption of indivisible techndogy are not restricted by ownership or class structure. We have found, however, that in 1972,-and still in 1980, though tubewells were owned by a minor fraction of total farm househdds (and predominan tly by the large and medium farmers), they were used by a substan tial proportion of farm households. Predictably, .the user-owner ratio was the highest in the case of the small farmers in all provinces. The relative importance of the small and medium farmers as owners of this techndogy increased over the period, particularly in the Punjab where tubewells are concen trated. The development of a hire market in tube well services has ~ven birth to a new entrepreneurial class in the rural areas. Inequalities in rural income are dwindling and benefits emanating from n\lW technology are shared. These conclusions are of vital importance because they negate the existing views and show that (i) the indivisibility of technology has not been a barrier to its adoption, and that (ii) the fact that the share of the small and medium farmers in the ownership of tubewells has increased gives support to the thesis that if a technology is profi table, farmers will adopt it where possible. Thus, the view that small farmers are conserva tive and resist change can no longer be sustained Further, it shows that the small and medium farm sector, in particular, holds the potential for investment in techndogy.

Rechtsventrikuläre Auswurffraktion Vergleich verschiedener Methoden der Angiographie und der Äquilibrium-Radionuklidventrikulographie

1987 ◽  
Vol 26 (01) ◽  
pp. 39-45
Author(s):  
U. Tebbe ◽  
E. Voth ◽  
R. Sciagra ◽  
W. Schultz ◽  
G. Neuhaus ◽  
...  
Keyword(s):  
Right Atrium ◽  
Pulmonary Valve ◽  
Heart Diseases ◽  
Correlation Coefficients ◽  
Radionuclide Ventriculography ◽  
Background Correction ◽  
Minor Effect ◽  
The Right ◽  
A Minor ◽  
Good Agreement

In 21 patients with various heart diseases RVEF was measured angiographically and by radionuclide ventriculography. Using biplane angiocardiography evaluation was performed by 7 different methods (Simpson’s rule, Dogde, Arcilla, Ferlinz, Duebel). Using equilibrium RNV, evaluation was performed by 9 modifications of analysis. Problems were evident to separate the right atrium from the ventricle and to define the site of the pulmonary valve. The results show that when using the various methods of angiography considerable variations of the absolute volumes occur, but least so with RVEF. When using RNV with one single enddiastolic ROI, the RVEF was much too low. By means of the enddiastolic/endsystolic Double-ROI-method a good agreement with angiography was found, with correlation coefficients up to r = 0.85. There was only a minor effect of background correction.

Phosphate sorption by soils as a measure of the phosphate requirement for pasture growth

1967 ◽  
Vol 18 (4) ◽  
pp. 601 ◽  
Author(s):  
PG Ozanne ◽  
TC Shaw
Keyword(s):  
Equilibrium Concentration ◽  
Correlation Coefficients ◽  
Laboratory Method ◽  
Phosphate Sorption ◽  
Soil Mixing ◽  
Equilibrium Concentrations ◽  
The Relationship ◽  
Pasture Plants ◽  
Different Soils

Development of a laboratory method for predicting the phosphate requirements of pasture plants, in pounds phosphorus per acre, is described. Measurement of the phosphate sorption by soil at a standard equilibrium concentration was used. Predictions made by using this method in the following year on different soils accounted for over 85% of the variability in phosphate requirement. A good correlation between phosphate sorbed and phosphate required was found. The relationship was linear over the range 0–500 p.p.m. of sorbed P. While different sampling depths, equilibrium concentrations, and degree of soil mixing affected the relationship, it remained linear and the correlation coefficients close to 0.9.

The relative importance of the total cell wall and quantity of digested cell wall in the regulation of the voluntary intake of grass hays by sheep

1975 ◽  
Vol 85 (1) ◽  
pp. 39-43 ◽  
Author(s):  
K. W. Moir ◽  
L. Laws ◽  
G. Blight
Keyword(s):  
Cell Wall ◽  
Organic Matter ◽  
Linear Model ◽  
Correlation Coefficients ◽  
Poor Quality ◽  
Total Cell ◽  
Relative Importance ◽  
Simple Correlation ◽  
Grass Breeding ◽  
Voluntary Intake

SUMMARYIn 18 digestibility experiments with sheep, 9 diets consisting of single-grass hays and 9 diets each consisting of equal quantities of a good and poor quality hay were fed. Correlations between the voluntary intake of organic matter, digested organic matter, total cell wall and digested cell wall in all possible combinations were investigated. There were no significant differences among the simple correlation coefficients for hays fed singly or as mixtures, even though they were eaten in very different amounts. The simple pooled correlationswere significant (P < 0·01) among voluntary intake, digested organic matter and cell wall. The cell wall was significantly correlated with digested cell wall, but there was no simple correlation between voluntary intake and digested cell wall. However, when considered together in a multiple linear model they explained 58% of the variation in voluntary intake compared with 43% explained by the total cell wall alone. The additional variation accounted for by the digested cell wall was significant (P < 0·05).The relative importance of the total cell wall and digested cell wall is discussed in relation to selection in grass breeding.

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